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3D-Printed Clock and Gears

These are the basic components of a clock 3D-printed by a Stratasys FDM 2000. The Stratasys FDM works by laying down "hot noddles" of ABS plastic and a sacrificial material that can be dissolved by water. The hot noodles are printed layer-by-layer and fuse together building finished-quality-level parts. With careful design, you can create captured moving parts, like the interlocking gears shown in the Slideshow.

This project dates to 2001 when I was at the MIT Media Lab. I was big on clocks, and was trying to design a fully 3D-printable clock. I imagined that after dissolving away the sacrificial material, you could wind the clock up and have it start ticking. I printed working gears, springs, and escapements in my attempts to test out each of the required components.

The escapement proved to be the biggest challenge. While it did work, the tolerances on the one shown were not quite good enough for it to work consistently. In the video, I have quite a large weight pulling on the escapement wheel and the pendulum moving briskly, but if the pendulum loses just a little bit of energy and doesn't make a full swing the escapement wheel doesn't lock, and instead, spins freely dropping the weight. The weight, which is out of the video frame, is connected to a spool on the center of the escapement wheel via a white string that is almost in visible in the video. The bed size of the Statasys (about a cubic foot) prevented me from building much larger versions of this escapement where the tolerances wouldn't be as much of an issue.

Obviously, nice escapements and clocks can be built by hand, and I encourage anyone mechanically-minded to at least visualize how escapement works, if not trying to build one yourself.

I've included the complete CAD files from the escapement shown here, so you can use my models as a starting point for your own creations. EJW 3D-printed clock.zip includes Autodesk Inventor files and solid model exports (stl and sat files).

it's called "Make Your Own Working Paper Clock". The design is adjustable and had the faceplate and hands and everything. I've had a copy of it since I was a little boy, when I was younger I was too scared I'd mess it up so I never tried it. I've decided to keep it in book form, lest it become rare some day. Some people have "probably" scanned it and the pdf is "probably" floating around the internet.

Ugh I am currently building the paper clock from this book... Very tedious very frustrating... I am having a lot of trouble with this clock because the main wheel (which took more than an hour to make, btw) seems to be warped because I decided to use rubber cement instead of regular white glue, and the rubber cement wasn't strong enough, so now the main wheel won't quite turn true (it turns wobbly) which causes problems with it meshing properly with the other wheels... AGHHHH sooo frustrating

just open the files in pepakura and click unfold. youll have to convert the file to a .obj (wavefront), .dxf(autocad 3d), .mqo(metasequoia), .3ds(3ds max), .lwo(lightwave), .stl(binary stl), .kml, or .kmz(both google earth4). you wont be able to save files unless you want to spend $40 to get it registered.

The force of gravity works both against and for the pendulum. We can agree that if you started a pendulum with nothing else touching it, no escapement mechanism, it would eventually stop due to gravity. Adding the escapement and weight, however, should keep the pendulum going as long as the weight hasn't reached the ground. The weight causes the escapement gear to want to rotate, and as the lever releases the gear, the gear pushes back on the lever and therefore the pendulum as well. This little push is what overcomes the losses due to gravity.

hi all, I work for a company that prints STL files directly into metal. This is more expensive than plastic, BUT, it's metal! This is not laser sintering, which is VERY expensive. Small parts are generally 3-5x more than plastic versions. Large projects are possible but it can get pricey. Go to: www.prommetal.com

Could it be the 3D printer has trouble making the fine points of the wheel as sharp and hard as one made of metal? If the wheel is free wheeling then would the distance between be the problem as for mentioned? And could this be a result of the tins being a fraction short, soft or something to this sort? Ross

The reason the escapement is behaving this way is that the two arms of the anchor have equal lengths(?). Making one arm a little bit shorter will case the entering pallet to enter the space between successive teeth (rather than on top of a tooth), exactly at the moment the other pallet looses contact with the escape-wheel. This brings the escape-wheel to a stop twice every full period of the pendulum.

In the video, I have quite a large weight pulling on the escapement wheel and the pendulum moving briskly, but if the pendulum loses just a little bit of energy and doesn't make a full swing the escapement wheel doesn't lock, and instead, spins freely dropping the weight. The weight, which is out of the video frame, is connected to a spool on the center of the escapement wheel via a white string that is almost in visible in the video.

The end of the pendulum has a bolt through it. It's not out of the frame; the whole contraption is on an optics table with a black edge that makes it appear like the pendulum is right at the edge of the frame. I added a much longer arm, bolted on to the pendulum, thinking exactly what you've suggested, but it didn't help much. While it did slow down the period, the added inertia would eventually prevent it from making a full swing and the escapement would just slip.

That would mean your pivot is a little high, right? In all the diagrams I've seen, you don't get complete disengagement, one or both points are still within the gear-just both not touching at one time (the one that is about to engage is about 1/2 a tooth off).

Your escapement is like the Graham escapement, but misses the crucial point: the dead-beat. This is because (although the entering pallet is curved; why?) it does not actually enter the space between successive teeth of the escape-wheel. Consequently, the period of the pendulum is not dictated by its length, but by it's moment of inertia and by the driving wheight, and the escapement can not be used for accurately measuring time. Please see also YouTube_BenvandeWaal.

bad news, the stl files have the pieces joined so I cant develop in to paper, it would take me much time to separate the pieces, unless you upload the 3d file with all the pieces in separete form, also It helps much if is in 3ds thanks :D

I have plenty of Legos sitting around, but the only electronic bits are part of a Lego train kit. I never managed to get a hold of a Mindstorms set (sob), and I have very few Technic parts. Then again, I could just wait until the lathe gets assembled and make one out of aluminum.

About This Instructable

Bio:Eric J. Wilhelm is the founder of Instructables. He has a Ph.D. from MIT in Mechanical Engineering. Eric believes in making technology accessible through understanding, and strives to inspire others ...read more »